The antioxidant properties of dietary phenolics are believed to be reduced in vivo because of their affinity for proteins. In this study we assessed the bioavailability of phenolics and the in vivo plasma antioxidant capacity after the consumption of blueberries (Vaccinium corymbosum L.) with and without milk. In a crossover design, 11 healthy human volunteers consumed either (a) 200 g of blueberries plus 200 ml of water or (b) 200 g of blueberries plus 200 ml of whole milk. Venous samples were collected at baseline and at 1, 2, and 5 h postconsumption. Ingestion of blueberries increased plasma levels of reducing and chain-breaking potential (+6.1%, p<0.001; +11.1%, p<0.05) and enhanced plasma concentrations of caffeic and ferulic acid. When blueberries and milk were ingested there was no increase in plasma antioxidant capacity. There was a reduction in the peak plasma concentrations of caffeic and ferulic acid (-49.7%, p<0.001, and -19.8%, p<0.05, respectively) as well as the overall absorption (AUC) of caffeic acid (p<0.001). The ingestion of blueberries in association with milk, thus, impairs the in vivo antioxidant properties of blueberries and reduces the absorption of caffeic acid.

That study used milk, not just protein. Do you eat your blueberries with milk?I'm sure there is plenty of reason to believe that protein reduces antioxidant properties of blueberries, but since the study used milk and not some sort of protein concentrate or isolate, it isn't really definitive.

In the abstract, the author mentions "protein" rather than milk protein, and a review I saw of this article said the take-home message was to avoid protein (in general) within a certain time window of eating blueberries, but I won't know what they're basing this on until I see the full article

In the abstract, the author mentions "protein" rather than milk protein, and a review I saw of this article said the take-home message was to avoid protein (in general) within a certain time window of eating blueberries, but I won't know what they're basing this on until I see the full article

I have no idea how to post a link to it, but anyone who wants it, bust me a PM with your email address and I'll ping it through.

In the abstract, the author mentions "protein" rather than milk protein, and a review I saw of this article said the take-home message was to avoid protein (in general) within a certain time window of eating blueberries, but I won't know what they're basing this on until I see the full article

I'll grab it after. SHIT this sucks. I wonder if using soy milk would be better? I can't believe I just typed that

The human diet provides a wide array of plant-derived phenolicswith antioxidant activity that helps the body to cope with oxidativestress [1]. The biological response to antioxidant-rich foods is criticallydetermined by the bioavailability of active molecules. The mostabundant phenolics in the diet are not necessarily those able to reachthe highest levels in human circulation, owing to the considerabledifferences in bioavailability. Human intervention studies have shownthat absorption of phenolics in the gastrointestinal tract is, typically,between 1 and 5% of the ingested dose [2]. Polyphenols can beabsorbed in the stomach and at the small intestine level by passivediffusion or active transport [3,4]. Once absorbed, the metabolism ofpolyphenols in humans implies a profound biotransformation throughenzymatic conjugation with sulfate, methyl, or glucuronide groups inboth the small intestine epithelial cells and the liver [4]. Thesemetabolites can reach a maximum concentration in plasma (Cmax)1?2 h after ingestion of phenolic-rich foods [5?7] and appear principallyin urine after 4?8h [8,9].

Variable amounts of ﬂavonoids, not absorbed in the uppergastrointestinal tract, reach the colon, where they are subjected tothe action of the colonic microﬂora, resulting in cleavage of glycosidiclinkages and the breakdown of the ﬂavonoid heterocycle into phenolicacids and aldehydes [10?14]. Thesemicrobial catabolites are absorbedinto the circulatory systemfromthe large intestine, reaching a Cmax ca.5 h postconsumption and, consequently, are able to exert biologicalactions [2].